Adhesives are utilized in a wide array of applications including packaging, in manufacturing consumer and industrial products, and in household applications. The type of adhesive needed is dependent upon the requirements of the application and the substrates to which it will be applied. Accordingly, countless different types of adhesive compositions have been developed to meet the demands of the applications in which they will be used. It is, of course, critical to select an adhesive that meets all of the physical and chemical requirements of a given application.
Adhesives are sometimes applied to roofing shingles to secure them to the roof structure to which they are being applied. The adhesive can be the sole means for affixing the roofing shingles to the structure or the adhesive can be used in conjunction with roofing nails or other mechanical means for affixing the shingles to the substrate. U.S. Pat. No. 6,753,362 described a cold bond adhesive composition that produces a strong bond between a polymeric capping membrane used in a roofing application and a roofing substrate. This composition is comprised of a homogeneous 60 to 75% solids mixture of (a) between about 0.5 weight percent and about 15 weight percent of a thermosetting styrene/isoprene/styrene block polymer containing up to 90% styrene; (b) between about 13 weight percent and about 30 weight percent of a aromatic hydrocarbon solvent containing from about 5 weight percent to about 20 weight percent aliphatic hydrocarbon; (c) between about 20 weight percent and about 70 weight percent a non-blown asphalt optionally containing a minor amount of blown asphalt; (d) between about 1 weight percent and about 10 weight percent of a metal silicate and (e) between about 0.1 weight percent and about 5 weight percent of a C6 to C16 alkoxyalkyl amine substituted ester of a C2 to C12 carboxylic acid as a surfactant.
In some cases self seal adhesive compositions are applied to the underside of roofing shingles and covered with a release tape at the factory where they are manufactured. This allows for the adhesive to be applied to the roofing shingles under the controlled environment of the factory which offers the advantage of consistency and reduced risk of contamination. The release tape keeps the adhesive from prematurely sticking to surfaces in an undesired manner during storage and transportation. The release tape can be removed from the underside of the roofing shingles at the site where it is being applied as a roof covering shortly before it is used. This can be done by simply pulling the release tape from the roofing shingle to expose the adhesive. Roofing shingles of this type are described by U.S. Pat. No. 6,813,866 and U.S. Pat. No. 6,895,724. The adhesive utilized in such applications is typically an asphalt composition that has been modified with a block copolymer, such as a styrene-butadiene-styrene triblock polymer, a styrene-isobutylene-styrene triblock polymer, or a styrene-ethylene-butadiene-styrene block polymer.
The utilization of block copolymers in such asphalt based adhesive compositions substantially increases cost. Polymer modified asphalts that are used in adhesive applications are also susceptible to phase separation which in turn can lead to instability over time. Accordingly, a lower cost self seal adhesive that does not phase separate and which possesses the characteristics needed for adhering asphalt based roofing shingles to roof structures is in demand.